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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/chromeos/file_system_provider/operations/read_file.h"
#include <limits>
#include <string>
#include "chrome/common/extensions/api/file_system_provider.h"
#include "chrome/common/extensions/api/file_system_provider_internal.h"
namespace chromeos {
namespace file_system_provider {
namespace operations {
namespace {
// Convert |value| into |output|. If parsing fails, then returns a negative
// value. Otherwise returns number of bytes written to the buffer.
int CopyRequestValueToBuffer(scoped_ptr<RequestValue> value,
net::IOBuffer* buffer,
int buffer_offset,
int buffer_length) {
using extensions::api::file_system_provider_internal::
ReadFileRequestedSuccess::Params;
const Params* params = value->read_file_success_params();
if (!params)
return -1;
const size_t chunk_size = params->data.length();
// Check for overflows.
if (chunk_size > static_cast<size_t>(buffer_length) - buffer_offset)
return -1;
memcpy(buffer->data() + buffer_offset, params->data.c_str(), chunk_size);
return chunk_size;
}
} // namespace
ReadFile::ReadFile(
extensions::EventRouter* event_router,
const ProvidedFileSystemInfo& file_system_info,
int file_handle,
net::IOBuffer* buffer,
int64 offset,
int length,
const ProvidedFileSystemInterface::ReadChunkReceivedCallback& callback)
: Operation(event_router, file_system_info),
file_handle_(file_handle),
buffer_(buffer),
offset_(offset),
length_(length),
current_offset_(0),
callback_(callback) {
}
ReadFile::~ReadFile() {
}
bool ReadFile::Execute(int request_id) {
scoped_ptr<base::ListValue> values(new base::ListValue);
values->AppendInteger(file_handle_);
values->AppendDouble(offset_);
values->AppendInteger(length_);
return SendEvent(
request_id,
extensions::api::file_system_provider::OnReadFileRequested::kEventName,
values.Pass());
}
void ReadFile::OnSuccess(int /* request_id */,
scoped_ptr<RequestValue> result,
bool has_next) {
const int copy_result = CopyRequestValueToBuffer(
result.Pass(), buffer_, current_offset_, length_);
DCHECK_LE(0, copy_result);
DCHECK(!has_next || copy_result > 0);
if (copy_result > 0)
current_offset_ += copy_result;
callback_.Run(copy_result, has_next, base::File::FILE_OK);
}
void ReadFile::OnError(int /* request_id */, base::File::Error error) {
callback_.Run(0 /* chunk_length */, false /* has_next */, error);
}
} // namespace operations
} // namespace file_system_provider
} // namespace chromeos
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